25 February 2025, Volume 20 Issue 1

    

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  Identification of virological factors affecting the degradation of hepatitis B virus small envelope protein

  Bao-Yu ZHANG Yong-Xiang Wang

  Journal of Microbes and Infections. 2025, 20(1): 1-8.

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  The envelope proteins of hepatitis B virus can be classified into large envelope protein (L), middle envelope protein (M) and small envelope protein (S), and S protein is the most abundant transmembrane protein in the viral envelope. The current treatment goal for chronic hepatitis B is functional cure. One of the important indicators of functional cure is the sustained disappearance of hepatitis B surface antigen (HBsAg) in the blood, but the mechanism of intracellular degradation of S protein is still unclear. In our previous work, we found that G12-CAR, a chimeric antigen receptor (CAR) targeting hepatitis B virus envelope proteins, inhibited S protein secretion and promoted its intracellular degradation. In this study, Huh-7 human hepatocellular carcinoma cells were transfected with different vectors to express S protein, and bafilomycin and bortezomib were used to inhibit lysosomal autophagy and proteasomal degradation. The intracellular expression products were identified using SDS-PAGE and Western blot, and the extracellular expression products were detected by ELISA. The results showed that S proteins could be degraded by lysosomal autophagy and proteasome pathways; some hepatitis B virus factors affected S protein degradation; L proteins affected intracellular degradation of S proteins; and the envelope protein mRNA 3'-UTR sequences in the HBV genome affected intracellular S protein degradation.
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  Research on Risk Factors for Severe/Critical COVID-19

  Journal of Microbes and Infections. 2025, 20(1): 9-15.

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  Predicting the risk of progression to severe/critical COVID-19 is crucial for optimizing clinical interventions and healthcare resource allocation. This retrospective study analyzed clinical data from 305 hospitalized COVID-19 patients admitted to Huashan Hospital between December 2022 and January 2023, aiming to identify risk factors and evaluate the predictive performance of a multifactorial model for classifying patients into severe/critical categories. Demographic characteristics, comorbidities, and laboratory parameters (including inflammatory markers, coagulation profiles, and cardiac biomarkers) were collected, with disease severity classified according to the Diagnosis and Treatment Protocol for Novel Coronavirus Infection (Trial Version 10). Multivariate logistic regression revealed that advanced age, decreased lymphocyte count, reduced hemoglobin levels, and elevated levels of C-reactive protein (CRP), interleukin-6 (IL-6), D-dimer, and brain natriuretic peptide (BNP) were independent risk factors for severe/critical classification. A combined predictive model incorporating these indicators achieved an area under the curve (AUC) of 0.748, significantly outperforming individual predictors (AUC range: 0.625–0.681). The findings suggest that integrating age, inflammatory response, coagulation dysfunction, and cardiac injury biomarkers can effectively identify high-risk COVID-19 patients, providing a scientific basis for early stratified management, precision treatment, and public health policymaking. This study also contributes evidence-based insights for addressing future emerging infectious disease outbreaks.
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  The detection and analysis of tractus genitalis mycoplasma in women patients of certain regional medical center in Shanghai

  Journal of Microbes and Infections. 2025, 20(1): 23-27.

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  The purpose of this study is to understand the infection and drug sensitivity of Mycoplasma hominis (Mh) and Ureaplasma urealyticum (Uu) in outpatient and in Wusong District, Baoshan, Shanghai, for clinical diagnosis and treatment. Provide scientific evidence. Mycoplasma culture identification and count drug sensitivity kit were used to carry out mycoplasma culture, identification and drug sensitivity test. A total of 413 cases were tested for mycoplasma culture + drug sensitivity test, the results displayed that 165 cases were positive for mycoplasma culture (39.95%), 17 cases with simple Mh infection (4.12%), simple 152 infection (36.80%), and 9 cases of mixed infection (2.18%). In simple Mh infection, the top five sensitivity rates from high to low are: doxytetramycin/methamycin, oxytetramycin, clindamycin and gatifloxacin. There is no significant difference between the first three (P>0.05). There is a significant difference between oxytetramycin/methamycin and clindamycin and gatifloxacin (P<0.05, P< 0.01); The top five doses of drug resistance are from low to high: strongmycin/methotromycin, oxycycline, gatifloxacin, methyl sulfomycin, and there is no significant difference between the five (P>0.05). In simple Uu infection, the top five sensitivity rates from high to low are: strongmycin/Mermomycin, thromycin, azithromycin and clarithromycin. The difference between the first three has no statistical significance (P>0.05). The difference between strong mythromycin/mectin and azithromycin or clarithromycin is statistically significant (P<0.0 1) The drug resistance rate is from low to high: oxycycline/methamycin, oxycycline, gatifloxacin, azithromycin/erythromycin/levofloxacin, and the resistance rate of oxymycin/methamphemycin is not statistically different from the latter two (P>0.05), and azithromycin/erythromycin/levofloxacin resistance. Rate differences are statistically significant (P<0.05). This study confirmed that when treating mycoplasma infection in the reproductive tract, we should try to choose mermondamycin, oxycycline or diamycin as much as possible. The alternative drugs for simple Mh and Uu infection are clindamycin and azithromycin respectively.
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  Diagnostic value of super-multiplex PCR targeted sequencing in invasive pulmonary aspergillosis

  Journal of Microbes and Infections. 2025, 20(1): 28-36.

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  Objective: This study investigates the role of multiplex PCR -based targeted next-generation sequencing (tNGS) in the diagnosis of invasive pulmonary aspergillosis (IPA). Methods: A total of 209 patients with clinical suspicion of IPA were included in this study from January to July 2023. Each patient underwent fiber bronchoscopy, and bronchoalveolar lavage fluid (BALF) was collected for analysis. tNGS, galactomannan (GM) testing, and Gram staining were performed on these samples. Additionally, we analyzed tNGS detection data from 13,452 BALF samples collected at our test center throughout 2023.. Results: Among the 209 BALF samples from suspected IPA patients, tNGS detected Aspergillus in 183 cases, yielding a positive rate of 87.6%. The species distribution revealed that aspergillus fumigatus had the highest detection rate (127 cases, 69.4%), followed by Aspergillus aflatus (43 cases, 23.5%), Aspergillus terreus (7 cases, 3.83%) and Aspergillus Niger (6 cases, 3.28%). Using a GM test threshold of ≥1.0, the detection rate of aspergillus was 70.3%, significantly lower than that of tNGS (P < 0.001), but notably higher than that from Gram staining smear (20.1%). Among the 183 tNGS positive samples, additional pathogens were detected in 168 cases, accounting for 91.8%. The sequence number of tNGS in patients with positive GM test was significantly higher than that in patients with negative GM test (P < 0.001). In addition, among the 13452 BALF samples, tNGS detected aspergillus in 2131 (13.7%) samples. Aspergillus fumigatus (56.9%) was the most commonly detected species, followed by Aspergillus aflatus (33.4%), Aspergillus Niger (3.5%) and Aspergillus terreus (1.7%), and more than two aspergillus species accounted for 4.5%. A total of 91.1% of the pathogens detected were associated with Aspergillus. awith the most common being (25.9%), Klebsiella pneumoniae (14.2%), Acinetobacter baumannii (12.6%), novel coronavirus (12.1%), Pseudomonas aeruginosa (9.53%) and Mycobacterium tuberculosis complex group (6.76%) . Conclusions:The tNGS technique has higher sensitivity and specificity than GM test in IPA diagnosis. Moreover, tNGS enables accurate identification of Aspergillus species and offers significant advantages in diagnosing mixed fungal infections..
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  Study on the difference of sensitivity detection methods of Klebsiella pneumoniae to ceftazidime/avibactam in vitro

  Journal of Microbes and Infections. 2025, 20(1): 37-42.

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  [Abstract] Objective: To investigate the clinical distribution and drug resistance of carbapenem-resistant Klebsiella pneumoniae in East Hospital Affiliated to Tongji University. To compare the detection rate and sensitivity of carbapenem-resistant Klebsiella pneumoniae isolates by several methods. To provide reference for the selection of clinical Klebsiella pneumoniae resistance detection methods. Methods: Klebsiella pneumoniae isolated from various specimens submitted for clinical examination in East Hospital Affiliated to Tongji University from October to December 2022 were collected, and imipenem, ertapenem or meropenem resistant Klebsiella pneumoniae were screened by paper diffusion preliminary screening method. 49 carbapenem-resistant Klebsiella pneumoniae (CRKP) were screened out of 82 strains. The detection rate of Klebsiella pneumoniae, distribution of departments, source of specimens, antimicrobial resistance and resistance to carbapenems were analyzed. The sensitivity of CRKP to imipenem was detected by instrument method, concentration gradient method (E-test method) and disk diffusion method, and the differences between the three methods were analyzed. Results: 82 strains of Klebsiella pneumoniae were mainly collected from neurology, neurosurgery, hepatobiliary and pancreatic surgery, central care unit, urology, endocrinology, functional neurology, emergency medicine, etc. The top three distribution were neurology (33 cases, 30.7%), neurosurgery (8 cases, 9.6%), hepatobiliary and pancreatic surgery (7 cases, 8.4%). The samples were mainly sputum (51.2%) and midstream urine (19.5%). Carbapenase-resistant Klebsiella pneumoniae: 49 cases. There were 39 KPC-positive strains (79.6%) and 6 NDM positive strains (12.2%). The sensitivity rates of CRKP to imipenem by instrument method, E-test method and disk diffusion method are respectively, showing high consistency and sensitivity. Anova analysis between KB value of disk diffusion method and MIC value of E-test method P> 0.05, indicating that there is no linear relationship between KB value and MIC value. Conclusion: Klebsiella pneumoniae clinically isolated in our hospital carried a variety of drug resistance genes, carbapenem resistance was mainly caused by KPC and NDM genes, and was resistant to dozens of commonly used clinical antibiotics. The sensitivity of CRKP to imipenem was higher by instrument, disk diffusion and E-test. Different drug sensitivity detection methods have their advantages and disadvantages. Surveillance and drug resistance screening of Klebsiella pneumoniae should be strengthened and clinical rational drug use should be guided to prevent the spread of CRKP in hospitals.
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  Clinical application of tandem dry fog hydrogen peroxide ventilator pipe disinfection device

  Journal of Microbes and Infections. 2025, 20(1): 43-47.

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  【Abstract】： Objective To develop a new disinfection device for the internal tubing of ventilators, and to assess its effectiveness. Methods The tandem device is designed to disinfect the internal tubing of ventilators with hydrogen peroxide (H2O2) dry mist that is produced by jet technique. The assessment was performed with 40 ventilators that were used by patients with infection. Cfu in air intake, air outlet, and internal tubing, was determined at the following time point, before disinfection, 1 hour after disinfection, and 4 hours after disinfection. The eligibility criteria were cfu<20 without any pathogenic bacteria. All data was subjected to statistical analysis. Results The qualified rate was 0% before disinfection by H2O2, while it was 100% after disinfection for 1 hour and 4 hours, and cfu in each detection sites was significantly lower after disinfection (p＜0.05). Conclusion The tandem H2O2 dry mist-disinfecting device is reliable and effective, and the expected effect could be achieved by 1-hour disinfection.
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  A case of lung infection in a patient with malignant tumor caused by Actinobacillus ureus

  Le Wang guo jian

  Journal of Microbes and Infections. 2025, 20(1): 48-52.

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  This article reports a case of pulmonary infection caused by Actinobacillus ureus in a patient with a malignant tumor and a literature review. This patient was infected with Actinobacillus ureus during hospitalisation for chemotherapy when the body's immune function was low. We communicated with clinicians during the testing process, performed drug susceptibility testing according to clinical needs, and assisted in the clinical treatment of the patient using cefoperazone sulbactam in combination with intravenous levofloxacin for anti-infective symptomatic treatment. Although Ureaplasma actinomycetemcomitans is generally recognised as a normal flora of the respiratory tract in clinical practice, the prevalence of infection with this organism is higher than the general level of recognition, according to the available literature; therefore, it should be regarded as a potential pathogen in susceptible patients in clinical practice. In this case, the laboratory characteristics and clinical manifestations of Actinobacillus ureus were studied and researched to increase the knowledge of medical practitioners about this pathogen, and to provide clinicians with a reference for the diagnosis of this type of disease.
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  Analysis of the Biological and Molecular Characteristics of a Rare Salmonella Strain Isolated from Changchun

  Journal of Microbes and Infections. 2025, 20(1): 53-58.

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  Abstract: This study aims to analyze the biological characteristics and molecular features of Salmonella Poona, a rare serotype of Salmonella, to provide scientific evidence for clinical treatment and prevention. Bacteriological identification, serotyping, drug sensitivity testing, and whole genome sequencing were employed to investigate its biological and molecular profiles. Results demonstrated that the strain was biochemically confirmed as Salmonella genus with serotype O22:Hz:H1、6. The isolate exhibited resistance to most antibiotics and harbored a diverse array of resistance and virulence genes. This research confirms the first isolation of a multidrug-resistant and highly virulent Salmonella Poona strain in Changchun City, highlighting the need for heightened attention to this pathogen.
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  The Pathogenic Mechanism of Outer Membrane Protein of Acinetobacter baumannii and Its Latest Research Progress

  Journal of Microbes and Infections. 2025, 20(1): 59-64.

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  Acinetobacter baumannii(AB) is a highly pathogenic Gram-negative bacterium with remarkable environmental adaptability and prolonged survival. It can infect multiple sites in the human body and has become one of the most common pathogens in hospital-acquired infections due to its extensive acquired drug resistance, making the study of its pathogenic mechanisms urgent. Outer membrane proteins (OMPs) are among the key virulence factors of AB, contributing to adhesion and invasion, biofilm formation, immune evasion, and induction of apoptosis. In recent years, significant progress has been made in research on AB OMPs, with advanced technologies such as proteomics, transcriptomics, and bioinformatics being widely applied. This review focuses on the pathogenic mechanisms of AB OMPs and the latest research advancements in this field.